Medical systems known from the state of the art with a medical device and with a supply unit have an isolating transformer for connection to an electric supply network. The isolating transformer causes a galvanic separation of the medical device or the supply unit from the supply network. Electric leakage currents are reduced hereby.
An interruption-free power supply unit, which can be connected to an electric supply network, is known from DE 38 138 68 A1. The interruption-free power supply unit has a frequency converter and an isolating transformer. The isolating transformer has a third winding, which is isolated from an input winding and an output winding and which is connected to a power converter, whose d.c. side is connected to a backup battery.